CVE-2021-21318Network attack vector

Series access manipulation via stale ACL updates

Published Feb 18, 2021 · Updated Aug 3, 2024

Incorrect authorization in Opencast before 9.2 allows remote authenticated users to alter series access via episode publication or removal. SearchServiceImpl replaces a series ACL with one episode's ACL and, during removal, fails to recalculate or delete the series index entry. An account permitted to publish, republish, or remove episodes can hide a public series, leave broader access than remaining episodes allow, or expose empty-series metadata.

CVSS severity5.4
Medium
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Opencast before 9.2 allows remote authenticated users to alter series access via episode publication or removal. SearchServiceImpl replaces a series ACL with one episode's ACL and, during removal, fails to recalculate or delete the series index entry. An account permitted to publish, republish, or remove episodes can hide a public series, leave broader access than remaining episodes allow, or expose empty-series metadata.

The record

CVE
CVE-2021-21318
Published
Feb 18, 2021
Updated
Aug 3, 2024
Vendor
Opencast
Product
Opencast
Classifications
CWE-863, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 9.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Opencast · Opencastversion=< 9.2

Published CVSS scores

5.4GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
5.5NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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